// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_BASE_DECODER_BUFFER_H_
#define MEDIA_BASE_DECODER_BUFFER_H_

#include <stddef.h>
#include <stdint.h>

#include <memory>
#include <string>
#include <utility>

#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/aligned_memory.h"
#include "base/memory/ref_counted.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "media/base/decrypt_config.h"
#include "media/base/media_export.h"
#include "media/base/timestamp_constants.h"

namespace media {

// A specialized buffer for interfacing with audio / video decoders.
//
// Specifically ensures that data is aligned and padded as necessary by the
// underlying decoding framework.  On desktop platforms this means memory is
// allocated using FFmpeg with particular alignment and padding requirements.
//
// Also includes decoder specific functionality for decryption.
//
// NOTE: It is illegal to call any method when end_of_stream() is true.
class MEDIA_EXPORT DecoderBuffer
    : public base::RefCountedThreadSafe<DecoderBuffer> {
public:
    enum {
        kPaddingSize = 32,
#if defined(ARCH_CPU_ARM_FAMILY)
        kAlignmentSize = 16
#else
        kAlignmentSize = 32
#endif
    };

    // Allocates buffer with |size| >= 0.  Buffer will be padded and aligned
    // as necessary, and |is_key_frame_| will default to false.
    explicit DecoderBuffer(size_t size);

    // Create a DecoderBuffer whose |data_| is copied from |data|.  Buffer will be
    // padded and aligned as necessary.  |data| must not be NULL and |size| >= 0.
    // The buffer's |is_key_frame_| will default to false.
    static scoped_refptr<DecoderBuffer> CopyFrom(const uint8_t* data,
        size_t size);

    // Create a DecoderBuffer whose |data_| is copied from |data| and |side_data_|
    // is copied from |side_data|. Buffers will be padded and aligned as necessary
    // Data pointers must not be NULL and sizes must be >= 0. The buffer's
    // |is_key_frame_| will default to false.
    static scoped_refptr<DecoderBuffer> CopyFrom(const uint8_t* data,
        size_t size,
        const uint8_t* side_data,
        size_t side_data_size);

    // Create a DecoderBuffer indicating we've reached end of stream.
    //
    // Calling any method other than end_of_stream() on the resulting buffer
    // is disallowed.
    static scoped_refptr<DecoderBuffer> CreateEOSBuffer();

    base::TimeDelta timestamp() const
    {
        DCHECK(!end_of_stream());
        return timestamp_;
    }

    // TODO(dalecurtis): This should be renamed at some point, but to avoid a yak
    // shave keep as a virtual with hacker_style() for now.
    virtual void set_timestamp(base::TimeDelta timestamp);

    base::TimeDelta duration() const
    {
        DCHECK(!end_of_stream());
        return duration_;
    }

    void set_duration(base::TimeDelta duration)
    {
        DCHECK(!end_of_stream());
        DCHECK(duration == kNoTimestamp || (duration >= base::TimeDelta() && duration != kInfiniteDuration))
            << duration.InSecondsF();
        duration_ = duration;
    }

    const uint8_t* data() const
    {
        DCHECK(!end_of_stream());
        return data_.get();
    }

    uint8_t* writable_data() const
    {
        DCHECK(!end_of_stream());
        return data_.get();
    }

    size_t data_size() const
    {
        DCHECK(!end_of_stream());
        return size_;
    }

    const uint8_t* side_data() const
    {
        DCHECK(!end_of_stream());
        return side_data_.get();
    }

    size_t side_data_size() const
    {
        DCHECK(!end_of_stream());
        return side_data_size_;
    }

    // A discard window indicates the amount of data which should be discard from
    // this buffer after decoding.  The first value is the amount of the front and
    // the second the amount off the back.  A value of kInfiniteDuration for the
    // first value indicates the entire buffer should be discarded; the second
    // value must be base::TimeDelta() in this case.
    typedef std::pair<base::TimeDelta, base::TimeDelta> DiscardPadding;
    const DiscardPadding& discard_padding() const
    {
        DCHECK(!end_of_stream());
        return discard_padding_;
    }

    void set_discard_padding(const DiscardPadding& discard_padding)
    {
        DCHECK(!end_of_stream());
        discard_padding_ = discard_padding;
    }

    const DecryptConfig* decrypt_config() const
    {
        DCHECK(!end_of_stream());
        return decrypt_config_.get();
    }

    void set_decrypt_config(std::unique_ptr<DecryptConfig> decrypt_config)
    {
        DCHECK(!end_of_stream());
        decrypt_config_ = std::move(decrypt_config);
    }

    // If there's no data in this buffer, it represents end of stream.
    bool end_of_stream() const
    {
        return data_ == NULL;
    }

    // Indicates this buffer is part of a splice around |splice_timestamp_|.
    // Returns kNoTimestamp if the buffer is not part of a splice.
    base::TimeDelta splice_timestamp() const
    {
        DCHECK(!end_of_stream());
        return splice_timestamp_;
    }

    // When set to anything but kNoTimestamp indicates this buffer is part of a
    // splice around |splice_timestamp|.
    void set_splice_timestamp(base::TimeDelta splice_timestamp)
    {
        DCHECK(!end_of_stream());
        splice_timestamp_ = splice_timestamp;
    }

    bool is_key_frame() const
    {
        DCHECK(!end_of_stream());
        return is_key_frame_;
    }

    void set_is_key_frame(bool is_key_frame)
    {
        DCHECK(!end_of_stream());
        is_key_frame_ = is_key_frame;
    }

    // Returns true if all fields in |buffer| matches this buffer
    // including |data_| and |side_data_|.
    bool MatchesForTesting(const DecoderBuffer& buffer) const;

    // Returns a human-readable string describing |*this|.
    std::string AsHumanReadableString() const;

    // Replaces any existing side data with data copied from |side_data|.
    void CopySideDataFrom(const uint8_t* side_data, size_t side_data_size);

protected:
    friend class base::RefCountedThreadSafe<DecoderBuffer>;

    // Allocates a buffer of size |size| >= 0 and copies |data| into it.  Buffer
    // will be padded and aligned as necessary.  If |data| is NULL then |data_| is
    // set to NULL and |buffer_size_| to 0.  |is_key_frame_| will default to
    // false.
    DecoderBuffer(const uint8_t* data,
        size_t size,
        const uint8_t* side_data,
        size_t side_data_size);
    virtual ~DecoderBuffer();

private:
    base::TimeDelta timestamp_;
    base::TimeDelta duration_;

    size_t size_;
    std::unique_ptr<uint8_t, base::AlignedFreeDeleter> data_;
    size_t side_data_size_;
    std::unique_ptr<uint8_t, base::AlignedFreeDeleter> side_data_;
    std::unique_ptr<DecryptConfig> decrypt_config_;
    DiscardPadding discard_padding_;
    base::TimeDelta splice_timestamp_;
    bool is_key_frame_;

    // Constructor helper method for memory allocations.
    void Initialize();

    DISALLOW_COPY_AND_ASSIGN(DecoderBuffer);
};

} // namespace media

#endif // MEDIA_BASE_DECODER_BUFFER_H_
